Service life early warning method and system of surge protection device

Abstract

The invention relates to the technical field of electrical protection devices, in particular to a service life early warning method and system for a surge protection device, and the method comprises the steps: carrying out the leakage current detection of the surge protection device, and recording the change condition of the detected leakage current as A; performing temperature detection on the surge protection device, and recording the detected temperature value as T; carrying out temperature detection on the environment where the surge protection device is located; when A is smaller than A1 and / or T is smaller than T1, the service life early warning grade is low; when A1 is smaller than or equal to Alt; a2 and / or when T1 is smaller than or equal to Tlt; t2 and Tgt; when t1, the service life early warning grade is middle; when A2 is less than or equal to Alt; a3 and / or when T2 is less than or equal to Tlt; t3 and Tgt; when t2, the service life early warning grade is high; when A > = A3 and / or when T > = T3 and Tgt; when t3, the service life is judged to be invalid; a3gt; a2gt; a1, T3gt; t2gt; t1, t3gt; t2gt; t2gt; t1. Therefore, the service life condition of the SPD is judged by detecting the leakage current, the temperature and the environment temperature of the SPD, and an accurate service life early warning level is given.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical protection devices, and in particular to a life warning method and system for a surge protector. Background Art

[0002] Surge protection device (SPD), also called lightning arrester, is an electronic device that provides safety protection for various electronic equipment, instruments and meters, and communication lines. When a spike current or voltage suddenly occurs in an electrical circuit or communication line due to external interference, the surge protector can conduct and shunt in a very short time, thereby preventing the surge from damaging other equipment in the circuit. SPD is an indispensable device for lightning protection of electronic equipment. Its function is to limit the instantaneous overvoltage that penetrates into the power line and signal transmission line to the voltage range that the equipment or system can withstand, or to discharge the strong lightning current into the ground to protect the protected equipment or system from impact.

[0003] At present, the existing SPD life expectancy judgment technologies mainly include the following: First, judging by detecting the magnitude of the power frequency leakage current of the varistor, and the power frequency leakage current of the varistor is composed of the superposition of the resistive leakage current and the capacitive leakage current. The junction capacitance of the varistor with low electrical level and large current is large, so the capacitive current is often much larger than the resistive current, resulting in the existing detection technology not being accurate in judging the SPD life warning; second, the life warning of the SPD is calculated by the number of lightning strikes and the peak value of the lightning strike. If the surge energy is very small each time the lightning strikes, it will have no effect on the performance of the SPD, so this method is also inaccurate. Therefore, how to accurately warn the life of the SPD has become a difficult problem that technicians in this field need to solve urgently.

[0004] It should be noted that the information disclosed in this background technology section is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes prior art already known to a person skilled in the art. Summary of the invention

[0005] The present invention provides a method for predicting the service life of a surge protector, which includes the following steps: detecting the leakage current of the surge protector, recording the change of the detected leakage current as A, and using it as the first judgment condition for predicting the service life of the surge protector; detecting the temperature of the surge protector, recording the detected temperature value as T, and using it as the second judgment condition for predicting the service life of the surge protector; detecting the temperature of the environment where the surge protector is located, and using the detected ambient temperature as the third judgment condition for predicting the service life of the surge protector; when A < A1 and / or T < T1, the service life warning level is low; when A1 ≤ A < A2 and / or when T1 ≤ T < T2 and T > t1, the service life warning level is medium; when A2 ≤ A < A3 and / or when T2 ≤ T < T3 and T > t2, the service life warning level is high; when A ≥ A3 and / or when T ≥ T3 and T > t3, the service life is determined to be invalid; where A1, A2, and A3 are preset leakage current thresholds, and A3 > A2 > A1; T1, T2, and T3 are preset temperature thresholds, and T3 > T2 > T1; t1, t2, and t3 are preset ambient temperature thresholds, and t3 > t2 > t1.

[0006] Further, the method for predicting the service life of the surge protector further includes the following steps: when detecting the temperature of the surge protector, recording the detected highest temperature value as T, and after 20 minutes, detecting the temperature of the surge protector again and recording it as TS. When TS < T, then T is regarded as invalid data and is not used for judging the judgment condition.

[0007] Further, the leakage current of the surge protector is detected by a leakage current detection circuit. The leakage current detection circuit includes a magnetic ring coil L1, a resistor R1, a resistor R2, a bridge rectifier DB2, a voltage stabilizing diode Z1, and a capacitor C1. The magnetic ring coil L1, the resistor R1, and the bridge rectifier DB2 are connected in parallel. The voltage stabilizing diode Z1 and the capacitor C1 are connected in parallel. The first end of the bridge rectifier DB2 is connected to the first end of the resistor R2, the second end of the bridge rectifier DB2 is connected to the first end of the voltage stabilizing diode Z1, and the second end of the resistor R2 is connected to the second end of the voltage stabilizing diode Z1.

[0008] Further, the bridge rectifier DB2 is a full bridge.

[0009] Further, the capacitor C1 is a ceramic capacitor.

[0010] Further, the temperature of the surge protector is detected by a temperature detection circuit. The temperature detection circuit includes a resistor R3 and a thermistor RT1. The resistor R3 and the thermistor RT1 are connected in series.

[0011] Further, the thermistor RT1 is attached to the heat-generating part of the surge protector.

[0012] Furthermore, the thermistor RT1 is an NTC thermistor.

[0013] Furthermore, the surge protector is provided with a display screen, and the display screen is used to display the life expectancy level information.

[0014] The present invention also provides a life warning system for a surge protector, and the life warning system for a surge protector adopts the above-mentioned life warning method for a surge protector.

[0015] The present invention provides a life warning method and system for surge protectors. Since the temperature of a surge protector increases with the increase of leakage current during the degradation process, the present invention detects the leakage current of the surge protector, the temperature of the surge protector, and the ambient temperature, and compares and calculates the three to determine the life warning situation and provide an accurate life warning level. It can also eliminate the noise generated when a surge occurs, thereby improving the accuracy of the warning.

[0016] Other features and beneficial effects of the present invention will be described in the following description, and some of the technical features and beneficial effects can be obviously derived from the description or understood by implementing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, some of the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 It is a flow chart of a life warning method for a surge protector provided by an embodiment of the present invention; Figure 2 is a circuit diagram of a leakage current detection circuit provided by an embodiment of the present invention; Figure 3 Schematic diagram of a temperature detection circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments; the technical features designed in different implementation modes of the present invention described below can be combined with each other as long as they do not conflict with each other; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0020] In the description of the present invention, it should be understood that the terms "center", "lateral", "up", "down", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more. In addition, the term "including" and any variation thereof all mean "at least including".

[0021] See also Figures 1 to 3 , Figure 1 is a flow chart of a life warning method for a surge protector provided by an embodiment of the present invention, Figure 2 is a circuit diagram of a leakage current detection circuit provided by an embodiment of the present invention, Figure 3 Schematic diagram of a temperature detection circuit provided by an embodiment of the present invention.

[0022] To achieve at least one of the above advantages or other advantages, an embodiment of the present invention provides a life warning method for a surge protector. As shown in the figure, the life warning method for a surge protector includes the following steps: The surge protector is tested for leakage current, and the change of the detected leakage current is recorded as A, which is used as the first judgment condition for the life warning of the surge protector; specifically, when the surge protector is degraded, the resistive leakage current of the varistor will gradually increase from the uA level (microcurrent refers to the current with a current intensity of the microampere level) to the mA level (milliampere current refers to the current with a current intensity of the milliampere level). The change of the leakage current of the surge protector is detected as condition 1 for the life warning of the surge protector; Perform temperature detection on the surge protector, record the detected temperature value as T, and use it as the second judgment condition for the life warning of the surge protector; as the deterioration current of the surge protector increases, the surface temperature of the surge protector rises, and the temperature of the surge protector is used as the judgment condition 2 for the life warning of the surge protector; Perform temperature detection on the environment where the surge protector is located, and use the detected ambient temperature as the third judgment condition for the life warning of the surge protector; When A < A1 and / or T < T1, the life warning level is low; a low life warning level means that the device state is good and the life is still long; When A1 ≤ A < A2 and / or when T1 ≤ T < T2 and T > t1, the life warning level is medium; a medium life warning level means that the device state is average and there may be problems with the life; When A2 ≤ A < A3 and / or when T2 ≤ T < T3 and T > t2, the life warning level is high; a high life warning level means that the device state is very poor and the life is very short; When A ≥ A3 and / or when T ≥ T3 and T > t3, the life is determined to be invalid; a life determined to be invalid means that the device is damaged; Among them, A1, A2, and A3 are preset leakage current thresholds, A3 > A2 > A1; T1, T2, and T3 are preset temperature thresholds, T3 > T2 > T1; t1, t2, and t3 are preset ambient temperature thresholds, t3 > t2 > t1.

[0023] Understood in conjunction with Table 1 below, Condition 2 and Condition 3 are in an AND relationship, that is, both of these conditions must be satisfied simultaneously to give the corresponding life warning judgment; Condition 1 and Conditions 2 and 3 are in an OR relationship, and as long as one of the conditions is satisfied, the corresponding life warning judgment can be made.

[0024] Table 1

[0025] It should be noted that in the case of no lightning surge, the detected leakage value and temperature value of the surge protector are the actual deterioration leakage current value and temperature value of the surge protector. This value is compared with the set warning level threshold, and when the set warning level range is met, the surge protector can display the corresponding life warning level.

[0026] In some embodiments, when there is a lightning surge, the temperature rise of the surge protector will necessarily change greatly in a short period of time. The greater the surge current passing through the surge protector, the higher the temperature rise of the surge protector, and it may even far exceed the warning maximum level T3 value given in Table 1 above. However, when the surge current has been discharged for a certain period of time (such as 20 minutes), the temperature of the surge protector returns to the value before the surge occurred. Therefore, in this embodiment, when a surge is detected, the maximum temperature value generated by the surge is recorded, but the temperature generated by the lightning surge is not used to determine the life warning level. That is, when detecting the temperature of the surge protector, the detected maximum temperature value is recorded as T, and after cooling for 20 minutes, the temperature of the surge protector is detected again and recorded as TS. If TS >= T, it means that the temperature rise of the surge protector is positive during this period and it is already in the process of accelerated deterioration; if the temperature TS detected after 20 minutes of cooling is < T, it means that the temperature rise is negative during this period, and then T is regarded as invalid data and not used as a judgment condition for determination, so as to avoid frequent false warnings during the thunderstorm season. That is to say, when a lightning surge occurs, after about 20 minutes when the surge passes, it can return to the normal temperature state; if the temperature of the surge protector is still rising after 20 minutes, that is, the temperature rise is positive, it is determined that the leakage current of the surge protector has deteriorated.

[0027] In some embodiments, as Figure 2 shown, the leakage current of the surge protector is detected by a leakage current detection circuit. The leakage current detection circuit includes a magnetic ring coil L1, a resistor R1, a resistor R2, a bridge rectifier DB2, a voltage stabilizing diode Z1, and a capacitor C1. The magnetic ring coil L1, the resistor R1, and the bridge rectifier DB2 are connected in parallel. The voltage stabilizing diode Z1 and the capacitor C1 are connected in parallel. The first end of the bridge rectifier DB2 is connected to the first end of the resistor R2, the second end of the bridge rectifier DB2 is connected to the first end of the voltage stabilizing diode Z1, and the second end of the resistor R2 is connected to the second end of the voltage stabilizing diode Z1. The magnetic ring coil L1 is sleeved into the wiring of the SPD and the power supply line. After the leakage current is generated during the SPD life, a corresponding induced voltage is generated in the magnetic ring coil L1, and a stable sine wave induced voltage is obtained across R1. After being rectified by DB2, then limited by R2 in current and protected by Z1 in voltage, and filtered by C1, it is sent to the ADC of the microcontroller for processing through program calculation to obtain the corresponding leakage current value; when the leakage current value reaches the corresponding set value, the OLED displays the corresponding life warning level prompt.

[0028] In some embodiments, the capacitor C1 is a ceramic capacitor. A ceramic capacitor is a capacitor that uses ceramic material as the dielectric, coats a metal film on the ceramic surface, and then uses it as an electrode after high-temperature sintering. It can be used in high-stability oscillation circuits as a loop, bypass capacitor, and padding capacitor.

[0029] In some embodiments, the bridge stack DB2 is a full bridge, and two diodes form connection points 1, 2, 3, and 4. Connection point 3 is the output end "positive pole" and is connected to resistor R2; connection point 4 is the output end "negative pole" and is connected to resistor Zener diode Z1 and capacitor C1.

[0030] In some embodiments, the temperature detection of the surge protector is performed through a temperature detection circuit, and the temperature detection circuit includes a resistor R3 and a thermistor RT1, and the resistor R3 and the thermistor RT1 are connected in series. The thermistor RT1 is attached to the heating part of the surge protector, that is, the thermistor RT1 is close to the heating part of the surge protector, so as to increase the action speed. When the temperature of the SPD rises, the resistance of the thermistor RT1 decreases, and the voltage also decreases accordingly, and is sent to the ADC of the microcontroller for analog-to-digital conversion. The microcontroller calculates the measured temperature value of the SPD and the ambient temperature value and then compares them with the set threshold, and at the same time satisfies the set threshold that the SPD temperature is greater than the ambient temperature, thereby calculating the life warning level of the SPD, and then sending it to the OLED for display. In some embodiments, the thermistor RT1 is an NTC thermistor.

[0031] In some embodiments, the surge protector is provided with a display screen, which is used to display the expected life level information, and the expected life level information is intuitively displayed on the body of the surge protector. The display screen may be an OLED screen.

[0032] An embodiment of the present invention further provides a life warning system for a surge protector, wherein the life warning system for a surge protector adopts the life warning method for a surge protector as described in the above embodiment.

[0033] In summary, the present invention provides a life warning method and system for a surge protector. Since the temperature of the surge protector increases with the increase of leakage current during the degradation process of the surge protector, the present invention detects the leakage current of the surge protector, the temperature of the surge protector, and the ambient temperature, and compares and calculates the three to determine the life warning situation and provide an accurate life warning level.

[0034] In addition, those skilled in the art should understand that, although there are many problems in the prior art, each embodiment or technical solution of the present invention can be improved in only one or several aspects, without having to solve all the technical problems listed in the prior art or background technology at the same time. Those skilled in the art should understand that the content not mentioned in a claim should not be used as a limitation on the claim.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A life warning method for a surge protector, characterized in that: The method for predicting the service life of the surge protector includes the following steps: Detect the leakage current of the surge protector, record the change of the detected leakage current as A, and use it as the first judgment condition for predicting the service life of the surge protector; Detect the temperature of the surge protector, record the detected temperature value as T, and use it as the second judgment condition for predicting the service life of the surge protector; Detect the temperature of the environment where the surge protector is located, and use the detected ambient temperature as the third judgment condition for predicting the service life of the surge protector; When A < A1 and / or T < T1, the service life warning level is low; When A1 ≤ A < A2 and / or when T1 ≤ T < T2 and T > t1, the service life warning level is medium; When A2 ≤ A < A3 and / or when T2 ≤ T < T3 and T > t2, the service life warning level is high; When A ≥ A3 and / or when T ≥ T3 and T > t3, the service life is determined to be invalid; Wherein, A1, A2, and A3 are preset leakage current thresholds, and A3 > A2 > A1; T1, T2, and T3 are preset temperature thresholds, and T3 > T2 > T1; t1, t2, and t3 are preset ambient temperature thresholds, and t3 > t2 > t1.

2. The life warning method of a surge protector according to claim 1, characterized in that: The method for predicting the service life of the surge protector further includes the following steps: when detecting the temperature of the surge protector, record the detected highest temperature value as T. After 20 minutes, detect the temperature of the surge protector again and record it as TS. When TS < T, then T is invalid data and no judgment condition determination is performed.

3. The life warning method of a surge protector according to claim 1, characterized in that: The leakage current of the surge protector is detected by a leakage current detection circuit. The leakage current detection circuit includes a magnetic ring coil L1, a resistor R1, a resistor R2, a bridge rectifier DB2, a voltage stabilizing diode Z1, and a capacitor C1. The magnetic ring coil L1, the resistor R1, and the bridge rectifier DB2 are connected in parallel. The voltage stabilizing diode Z1 and the capacitor C1 are connected in parallel. The first end of the bridge rectifier DB2 is connected to the first end of the resistor R2. The second end of the bridge rectifier DB2 is connected to the first end of the voltage stabilizing diode Z1. The second end of the resistor R2 is connected to the second end of the voltage stabilizing diode Z1.

4. The life warning method of a surge protector according to claim 3, characterized in that: The bridge rectifier DB2 is a full bridge.

5. The life warning method of a surge protector according to claim 3, characterized in that: The capacitor C1 uses a ceramic capacitor.

6. The life warning method of a surge protector according to claim 1, characterized in that: The temperature is detected by a temperature detection circuit. The temperature detection circuit includes a resistor R3 and a thermistor RT1. The resistor R3 and the thermistor RT1 are connected in series.

7. The life warning method of a surge protector according to claim 6, characterized in that: The thermistor RT1 is attached to the heat-generating part of the surge protector.

8. The life warning method of a surge protector according to claim 6, characterized in that: The thermistor RT1 is an NTC thermistor.

9. The life warning method of a surge protector according to claim 1, characterized in that: A display screen is provided on the surge protector, and the display screen is used to display the level information of the service life warning.

10. A life warning system for a surge protector, characterized in that: The service life warning system of the surge protector adopts the method for predicting the service life of the surge protector according to any one of claims 1 to 9.

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